Add docker model package command

[ekcasey]

Adds docker model package command:

Usage:  docker model package --gguf <path> [--license <path>...] --push TARGET

package a model

Options:
      --gguf string           absolute path to gguf file (required)
  -l, --license stringArray   absolute path to a license file
      --push                  push to registry (required)

Things to note:

• --push flag is required now. This is a bit awkward but allows us to default to local packaging when we add this in the future.
• --gguf is required and must point at a local file for now, but we will support building from other sources in the future

[xenoscopic]

You'll need to rebase on main where desktopClient is now a global in the commands package, but other than removing it from the newPackageCmd constructor, there shouldn't be any other changes.

[xenoscopic]

nit: Maybe append the version?